FETs do not turn off at zero-crossing currents

rcarlyle / StepperSim

Simulates stepper motor driver systems

MIT License

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FETs do not turn off at zero-crossing currents #4

Open rcarlyle opened 9 years ago

rcarlyle commented 9 years ago

This behavior is not clearly specified in the datasheets, but I believe the drive FETs turn off when current approaches zero during a zero-crossing microstep.

rcarlyle commented 8 years ago

The only real impact this has is that it may reduce/prevent negative currents when back-emf is extremely large. So it's already only an issue at the edge of the model's applicability range.

What I'm not sure about is whether the FET free-wheel diode behavior allows negative currents or not. If so, the current model behavior isn't that far off from reality.